In recent years, there has been a demand for rotationally manipulated volume controls and encoders which are mounted in AV devices and in-vehicle air-conditioning systems and which produce clicking sounds at a time of manipulation together with feeling of manipulation transmitted to the hand when they are rotationally manipulated.
Conventional, rotary manipulation type electronic devices are now described taking a rotationally manipulated encoder as an example by referring to the drawings.
FIG. 12 is a cross-sectional view of a conventional, rotationally manipulated encoder. FIG. 13 is an exploded perspective view of the conventional, rotationally manipulated encoder. In these figures, base body 1 has a central cylindrically shaped portion forming hollow portion 1A and is substantially annular. The upper side of portion 1A is open. Three fixed contacts 2 consisting of a common contact and two contacts for signals are disposed on the bottom surface of the opening portion. These fixed contacts 2 are arranged on the same circumference and insulated from each other by 120° intervals. Contact terminal 3A for a signal, contact terminal 3B for a signal, and common contact terminal 3C are electrically connected with three fixed contacts 2, respectively. These terminals extend outwardly as one row from terminal leading portion 1C protruding from the side wall of base body 1. These terminals 3A, 3B, and 3C constitute terminal portion 3.
Rotary body 5 has cylindrical portion 5B and flange portion 5C located below cylindrical portion 5B where central hole 5A is formed. Uneven portion 5D is formed on an entire top surface of flange portion 5C. Sliding contact 4 is fixed to the bottom surface of flange portion 5C. Sliding contact 4 has contact portions 4A at three locations which are circumferentially equally spaced from each other by 120° to produce ON/OFF signals by making sliding motion on three fixed contacts 2. In rotary body 5, the inner surface of cylindrical portion 5B is in contact with outer surface of inner wall 1B forming hollow portion 1A of base body 1. The rotary body 5 is fitted with base body 1 rotatably.
Cover plate 6 covers the opening portion of base body 1. Upper portions of cylindrical portion 5B of rotary body 5 and of wall 1B of base body 1 protrude from center hole 6A. The cover plate is made of a metal plate and crimped around base body 1. Annular leaf spring 7 is mounted to the bottom surface of cover plate 6.
This leaf spring 7 has horizontal portions whose both ends are bent obliquely downwardly as viewed from a side. Downwardly protruding protrusive portions 7A are formed in opposite positions which are bent as described above. Two protrusive portions 7A are in elastic contact with uneven portion 5D formed on the top surface of flange portion 5C of the above-described rotary body 5. Cover plate 6 is crimped to base body 1.
In the structure described so far, if cylindrical portion 5B of rotary body 5 protruding upwardly from center hole 6A in cover plate 6 is rotationally manipulated, contact portions 4A of sliding contact 4 on the bottom surface of flange portion 5C slide on fixed contacts 2 that are formed on the bottom surface of the opening portion of base body 1. A train of ON/OFF signals is produced between terminals 3A and 3C electrically connected with fixed contacts 2. A second train of ON/OFF signals is produced between terminals 3B and 3C. Processing corresponding to the direction of rotation is performed in a signal processing circuit in the installed device by the two trains of ON/OFF signals. For example, a function of increasing or reducing the volume is activated.
Because of the rotation of this rotary body 5, protrusive portions 7A at the two locations of leaf spring 7 fixed to the bottom surface of cover plate 6 make sliding motion while making elastic contact with uneven portion 5D formed on the top surface of flange portion 5C of rotary body 5. Consequently, a feeling of clicking (feeling of moderateness) corresponding to the position of uneven portion 5D is produced.
For example, Japanese Patent Unexamined Publication No. 1998-199371 is known as prior art documentary information associated with the invention.
However, in the above-described conventional, rotationally manipulated encoder (rotary manipulation type electronic device), a sound of manipulation produced as a result of rotational manipulation of rotary body 5 is only a low-pitched, dull sound. Therefore, there is the problem that it is difficult to produce clicking sound of manipulation, which is a demand from the market.